If the issue is not due to incomplete McAfee uninstall it could be caused by corruption in the Windows Management Instrumentation (WMI).

Run these commands from the command prompt.

Click Start, Run and type CMD.EXE

Note: For Vista and Windows 7, 8, 10 you need to open Command Prompt window as an administrator. To do so, click Start, click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.

For all OS:

Note: To save time and effort copy and paste the commands.

Net stop winmgmt (answer yes to any questions asked)

cd C:/Windows/system32/wbem

xcopy Repository Repository.old

rmdir /s Repository (answer yes to any questions asked)

Net start winmgmt

For Windows XP:

rundll32 wbemupgd, UpgradeRepositor

For Vista and Windows 7, 8, 10 :

winmgmt /salvagerepository

For all OS run these commands:

cd /d %windir%\system32\wbem

for %i in (*.dll) do RegSVR32 -s %i

for %i in (*.exe) do %i /RegServer

After running "for %i in (*.exe) do %i /RegServer" the above pop up window will appear. Just X out / close the window.